In a liquid crystal display apparatus, a polarizing plate is normally placed in a side closer to an image display surface than a liquid crystal cell. The polarizing plate normally includes a polarizer, such as a polyvinyl alcohol film, that is dyed with iodine or the like and stretched, and a protective film that is affixed to one surface of the polarizer and used for protecting the polarizer.
Conventionally, films comprising cellulose esters represented by triacetylcellulose have been used as protective films. This is based on an advantage that, e.g., water remaining in polarizers can be dried through the cellulose ester films when polarizing plates are produced since the cellulose esters are excellent in transparency and optical isotropy and have appropriate water permeability.
However, there have been problems such as a rise in transmittance due to discoloration and a decrease in polarization degree, caused by conducting a humidity test, because of a cellulose ester having an excessively high water vapor permeability rate. In order to solve the problems, a polarizing plate in which cycloolefin resin is used as a protective film has been proposed (for example, see Japanese Patent Laid-Open No. H06-51117). In addition, it has been desired that general-purpose films that have been inexpensively available on the market compared to cellulose ester films or have been able to be produced by simple methods have been used as protective films in order to improve durability. For example, it has been attempted to utilize a polyester film such as polyethylene terephthalate instead of the cellulose ester films (for example, see Japanese Patent Laid-Open No. 2007-279243).